A preparation method of a sulfur-vanadium co-doped bismuth tungstate visible light catalyst

Abstract

The present application relates to a kind of preparation methods of sulfur vanadium co-doped bismuth tungstate visible light catalyst, the catalyst is assisted by urea hydrothermal method, with sodium tungstate, bismuth nitrate, thiourea, citric acid, ammonium metavanadate, urea as raw material, configuration certain concentration of thiourea and citric acid aqueous solution as sulfur source;Configuration certain concentration of ammonium metavanadate aqueous solution as vanadium source.Sulfur source and vanadium source are mixed after drop by drop to be added to bismuth nitrate solution, after stirring, transfer to hydrothermal kettle, the hydrothermal kettle is placed in blast oven and hydrothermal treatment cooling, centrifugal separation product, washing and drying obtain sulfur vanadium co-doped BWO visible light catalyst.The method is obtained by one-step hydrothermal treatment flower cluster of bismuth tungstate nanosheet composition, simple process, low equipment requirement, the composite photocatalyst prepared has stronger response under visible light condition, has higher application value in pollution control, environmental protection, new energy preparation and other fields.

Description

Technical Field

[0001] This invention relates to a method for preparing a vanadium-sulfur co-doped bismuth tungstate visible light photocatalyst, and a method for preparing a vanadium-sulfur co-doped bismuth tungstate visible light photocatalyst prepared in a one-step hydrothermal reactor. This preparation method can broaden the visible light response range of the photocatalyst and improve the catalytic efficiency. Background Technology

[0002] In recent years, environmental pollution has become increasingly serious, and energy shortages have become an urgent issue. Faced with these two major crises, scientific research on pollution control and environmental protection has been launched. Using semiconductors as catalysts and utilizing sunlight to catalyze the oxidation and degradation of pollutants has become a hot topic in environmental protection scientific research as an effective method for pollution control. Against this research background, researchers from various countries have developed a variety of semiconductor nanomaterials, such as titanium dioxide, zinc oxide, and tungsten trioxide, for the treatment of pollutants and the acquisition of new energy sources. Taking titanium dioxide as an example, although nano-titanium dioxide has outstanding advantages such as high stability, strong photocatalytic ability, and non-toxicity and non-polluting properties, its band gap is 3.2 electron volts. This means that titanium dioxide can only absorb incident photons with wavelengths less than 387 nanometers, and its light absorption is limited to the ultraviolet region, which accounts for only 5% of the sunlight reaching the ground. Visible light accounts for 45% of solar energy, while the actual solar radiation energy reaching the Earth's surface is concentrated in the wavelength range of 460-500 nanometers. Therefore, how to efficiently utilize natural light for photocatalytic reactions and develop photocatalysts that can be excited by visible light are increasingly attracting people's interest.

[0003] In recent years, more researchers have focused on finding biphasic metal oxides with different crystal morphologies to expand the light absorption range into the visible light region in order to develop novel photocatalysts. Many recent studies have found that bismuth tungstate (Bi₂WO₆) has a layered structure containing perovskite-type sheets, exhibiting dielectric, luminescent, ionizing, and catalytic properties, and is widely used in related fields (Ju Wu, Fang Duan, et al, J. Phys. Chem. C 2007, 111, 12866-12871). Crucially, bismuth tungstate possesses visible light photocatalytic performance, which can be used for photocatalytic water splitting and degradation of organic pollutants under visible light (Dekun Ma, Shaoming Huang, et al, J. Phys. Chem. C 2009, 113, 4369–4374). Guisheng Li et al. synthesized microspheres composed of bismuth tungstate nanosheets stacked in any direction (Guisheng Li, Dieqing Zhang, et al, Environ. Sci. Technol. 2010, 44, 4276–4281). However, the nanosheets that make up the microspheres are completely grown together and cannot be separated, and the center of the sphere is a solid structure.

[0004] Doping with various non-metallic elements or transition metals such as carbon, fluorine, nitrogen, sulfur, vanadium, iron, and nickel can improve photocatalytic activity and extend the visible light response range. However, to date, there have been no reports on sulfur-vanadium co-doped titanium dioxide photocatalysts. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a bismuth tungstate visible light photocatalyst co-doped with vanadium and sulfur. This method uses a relatively simple process to prepare a bismuth tungstate visible light photocatalyst with high catalytic degradation efficiency and to broaden its visible light response range.

[0006] The method for preparing the vanadium-sulfur co-doped bismuth tungstate photocatalyst of the present invention uses sodium tungstate, bismuth nitrate, thiourea, citric acid, ammonium metavanadate, and urea as raw materials to prepare a vanadium-sulfur co-doped bismuth tungstate dioxide visible light photocatalyst, comprising the following steps:

[0007] (1) Dissolve 0.05 g of urea in deionized water and stir until dissolved. Add a certain amount of bismuth nitrate and sodium tungstate and stir until clear. This is solution A.

[0008] (2) Prepare a sulfur source by mixing a certain concentration of thiourea and citric acid in deionized water. Prepare a vanadium source by mixing a certain concentration of ammonium metavanadate and oxalic acid in deionized water.

[0009] (3) After mixing the sulfur source and vanadium source, add them dropwise to solution A and stir until the solution becomes a sol.

[0010] (4) The sol was transferred to a reaction vessel and hydrothermally treated at 180°C for 20 hours. After cooling, the product was separated by centrifugation and washed three times alternately with deionized water and anhydrous ethanol. The product was then dried at 80°C. Sample S / V-BWO was obtained.

[0011] In a preferred embodiment of the present invention, the molar ratio of bismuth nitrate to sodium tungstate is 2:1, and the thiourea and citric acid aqueous solution is a sulfur source; the molar ratio of thiourea to BWO is 1:100 to 1:5.

[0012] In another preferred embodiment of the present invention, ammonium metavanadate and an aqueous solution of oxalic acid are configured as vanadium sources; the molar ratio of ammonium metavanadate to BWO is 1:100 to 1:20.

[0013] In another preferred embodiment of the present invention, the sulfur source and the vanadium source are first mixed, and then added dropwise to the tungsten source.

[0014] This catalyst was prepared using a urea-assisted hydrothermal method, with sodium tungstate, bismuth nitrate, thiourea, citric acid, ammonium metavanadate, and urea as raw materials. A certain concentration of thiourea and citric acid aqueous solution was prepared as the sulfur source; a certain concentration of ammonium metavanadate aqueous solution was prepared as the vanadium source. The molar ratio of bismuth nitrate to sodium tungstate was 2:1, the molar ratio of thiourea to bismuth tungstate (BWO) was 1:100–1:5, and the molar ratio of ammonium metavanadate to bismuth tungstate (BWO) was 1:100–1:20. After mixing the sulfur and vanadium sources, the mixture was added dropwise to the bismuth nitrate solution. After stirring for 20 minutes, the mixture was transferred to a hydrothermal reactor, which was then placed in a 180°C forced-air oven for hydrothermal treatment for 20 hours. After cooling, the product was centrifuged and washed three times alternately with deionized water and anhydrous ethanol, and then dried at 80°C to obtain the sulfur-vanadium co-doped BWO visible light catalyst. This method yields flower clusters composed of bismuth tungstate nanosheets through a one-step hydrothermal treatment. The process is simple, requires minimal equipment, and the prepared composite photocatalyst exhibits a strong response under visible light conditions. It has high application value in pollution control, environmental protection, and new energy preparation.

[0015] The performance evaluation of the vanadium-sulfur co-doped bismuth tungstate visible light photocatalyst was conducted in a quartz glass tube. The evaluation sample was a 40 mg / L reactive blue dye solution, and the photocatalyst concentration was 1 mg / mL. The suspension was stirred for 1 h. The suspension was then exposed to a xenon lamp and subjected to photocatalytic degradation under filtered ultraviolet light for 300 min. Finally, the suspension was centrifuged at 12000 rpm for 10 min. The concentration of reactive blue in the supernatant was measured using a spectrophotometer, and the photocatalytic degradation rate of reactive blue was calculated. Attached Figure Description

[0016] Figure 1This is the UV-Vis absorption spectrum of the bismuth tungstate photocatalyst co-doped with vanadium sulfide in Example 1;

[0017] Figure 2 This is a SEM image of the bismuth tungstate photocatalyst co-doped with vanadium and sulfur in Example 1. Detailed Implementation

[0018] The embodiments of the present invention are described in detail below: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and operation processes. However, the scope of protection of the present invention is not limited to the following embodiments:

[0019] Example 1

[0020] A bismuth tungstate-sulfur co-doped visible light catalyst is prepared using sodium tungstate, bismuth nitrate, thiourea, citric acid, ammonium metavanadate, and urea as raw materials, according to the following steps:

[0021] (1) In a 100 mL transparent beaker, add 80 mL of deionized water and 0.05 g of urea and stir to dissolve; add bismuth nitrate pentahydrate and stir until clear, then add sodium tungstate dihydrate, wherein the molar ratio of bismuth nitrate to sodium tungstate is 2:1, stir for 20 minutes to obtain solution A;

[0022] (2) Citric acid and thiourea are added sequentially to deionized water and stirred for 2 hours as a sulfur source. The molar ratio of citric acid to thiourea is 1.2:1 and the molar ratio of thiourea to BWO is 1:100. An aqueous solution of ammonium metavanadate and oxalic acid is prepared in deionized water as a vanadium source. The molar ratio of oxalic acid to ammonium metavanadate is 2:1 and the molar ratio of ammonium metavanadate to BWO is 1:20.

[0023] (3) The sulfur source aqueous solution and the vanadium source aqueous solution are mixed and added dropwise to solution A. During this process, the mixture is stirred vigorously for 4 hours until the solution becomes a sol.

[0024] (4) The obtained sol was transferred to a reaction vessel, hydrothermally treated at 180°C for 20 hours, cooled, centrifuged to separate the product, and washed three times with deionized water and anhydrous ethanol alternately. The product was then dried at 80°C to obtain the bismuth tungstate visible light catalyst sample S / V-BWO co-doped with vanadium sulfide.

[0025] The catalytic performance of the prepared vanadium-sulfur co-doped photocatalyst was evaluated under the aforementioned experimental conditions, and the degradation rate of active blue was determined to be 51.6%.

[0026] Example 2

[0027] A bismuth tungstate visible light catalyst co-doped with vanadium sulfide was prepared according to the same steps (1), (3), and (4) as in Example 1, as follows:

[0028] (1) In a 100 mL transparent beaker, add 80 mL of deionized water and 0.05 g of urea and stir to dissolve; then add bismuth nitrate pentahydrate and stir until clear, then add sodium tungstate dihydrate. The molar ratio of bismuth nitrate to sodium tungstate is 2:1. Stir for 20 minutes to obtain solution A.

[0029] (2) Citric acid and thiourea were added to deionized water in sequence and stirred for 2 hours as a sulfur source. The molar ratio of citric acid to thiourea was 1.2:1 and the molar ratio of thiourea to BWO was 1:20. Oxalic acid and ammonium metavanadate were added to deionized water and stirred for 2 hours as a vanadium source. The molar ratio of oxalic acid to ammonium metavanadate was 2:1 and the molar ratio of ammonium metavanadate to BWO was 1:50.

[0030] (3) The above-mentioned sulfur source and vanadium source aqueous solutions were mixed and added dropwise to solution A. During this process, the mixture was stirred vigorously for 4 hours to obtain a sol.

[0031] (4) The obtained sol was transferred to the reaction vessel, and the reaction vessel was placed in a 180°C forced-air oven for hydrothermal treatment for 20 hours. After cooling, the product was separated by centrifugation and washed three times with deionized water and anhydrous ethanol alternately. The product was then dried at 80°C to obtain sample S / V-BWO.

[0032] The catalytic performance of the prepared vanadium-sulfur co-doped photocatalyst was evaluated under the aforementioned experimental conditions, and the degradation rate of active blue was determined to be 74.8%.

[0033] Example 3

[0034] A bismuth tungstate visible light catalyst co-doped with vanadium sulfide was prepared according to the same steps (1), (3), and (4) as in Example 1, as follows:

[0035] (1) In a 100 mL transparent beaker, add 80 mL of deionized water and 0.05 g of urea, and stir to dissolve. Then add bismuth nitrate pentahydrate, stir until clear, and then add sodium tungstate dihydrate. The molar ratio of bismuth nitrate to sodium tungstate is 2:1. Stir for 20 minutes to obtain solution A.

[0036] (2) Citric acid and thiourea were added to deionized water in sequence and stirred for 2 hours as a sulfur source. The molar ratio of citric acid to thiourea was 1.2:1 and the molar ratio of thiourea to BWO was 1:10. Oxalic acid and ammonium metavanadate were added to deionized water and stirred for 2 hours as a vanadium source. The molar ratio of oxalic acid to ammonium metavanadate was 2:1 and the molar ratio of ammonium metavanadate to BWO was 1:50.

[0037] (3) After the above-mentioned sulfur source and vanadium source aqueous solutions are mixed evenly, they are added dropwise to solution A. During this process, the mixture is stirred vigorously for 4 hours to obtain a sol.

[0038] (4) The obtained sol was transferred to the reaction vessel, and the reaction vessel was placed in a 180°C forced-air oven for hydrothermal treatment for 20 hours. After cooling, the product was separated by centrifugation and washed three times with deionized water and anhydrous ethanol alternately. The product was then dried at 80°C to obtain sample S / V-BWO.

[0039] The catalytic performance of the prepared vanadium-sulfur co-doped photocatalyst was evaluated under the aforementioned experimental conditions, and the degradation rate of active blue was determined to be 80.2%.

[0040] Example 4

[0041] A bismuth tungstate visible light catalyst co-doped with vanadium sulfide was prepared according to the same steps (1), (3), and (4) as in Example 1, as follows:

[0042] (1) In a 100 mL transparent beaker, add 80 mL of deionized water and 0.05 g of urea and stir to dissolve; then add bismuth nitrate pentahydrate and stir until clear, then add sodium tungstate dihydrate. The molar ratio of bismuth nitrate to sodium tungstate is 2:1. Stir for 20 minutes to obtain solution A.

[0043] (2) Citric acid and thiourea were added to deionized water in sequence and stirred for 2 hours as a sulfur source. The molar ratio of citric acid to thiourea was 1.2:1 and the molar ratio of thiourea to BWO was 1:5. Oxalic acid and ammonium metavanadate were added to deionized water and stirred for 2 hours as a vanadium source. The molar ratio of oxalic acid to ammonium metavanadate was 2:1 and the molar ratio of ammonium metavanadate to BWO was 1:100.

[0044] (3) After the above-mentioned sulfur source and vanadium source aqueous solutions are mixed evenly, they are added dropwise to solution A. During this process, the mixture is stirred vigorously for 4 hours to obtain a sol.

[0045] (4) The obtained sol was transferred to the reaction vessel, and the reaction vessel was placed in a 180°C forced-air oven for hydrothermal treatment for 20 hours. After cooling, the product was separated by centrifugation and washed three times with deionized water and anhydrous ethanol alternately. The product was then dried at 80°C to obtain sample S / V-BWO.

[0046] The catalytic performance of the prepared vanadium-sulfur co-doped photocatalyst was evaluated under the aforementioned experimental conditions, and the degradation rate of active blue was determined to be 92.9%.

[0047] Example 5

[0048] A bismuth tungstate visible light catalyst co-doped with vanadium sulfide was prepared according to the same steps (1), (3), and (4) as in Example 1, as follows:

[0049] (1) In a 100 mL transparent beaker, add 80 mL of deionized water and 0.05 g of urea, and stir to dissolve. Then add bismuth nitrate pentahydrate, stir until clear, and then add sodium tungstate dihydrate. The molar ratio of bismuth nitrate to sodium tungstate is 2:1. Stir for 20 minutes to obtain solution A.

[0050] (2) Citric acid and thiourea were added to deionized water in sequence and stirred for 2 hours as a sulfur source. The molar ratio of citric acid to thiourea was 1.2:1 and the molar ratio of thiourea to BWO was 1:5. Oxalic acid and ammonium metavanadate were added to deionized water and stirred for 2 hours as a vanadium source. The molar ratio of oxalic acid to ammonium metavanadate was 2:1 and the molar ratio of ammonium metavanadate to BWO was 1:20.

[0051] (3) After the above-mentioned sulfur source and vanadium source aqueous solutions are mixed evenly, they are added dropwise to solution A. During this process, the mixture is stirred vigorously for 4 hours to obtain a sol.

[0052] (4) The obtained sol was transferred to the reaction vessel, and the reaction vessel was placed in a 180°C forced-air oven for hydrothermal treatment for 20 hours. After cooling, the product was separated by centrifugation and washed three times with deionized water and anhydrous ethanol alternately. The product was then dried at 80°C to obtain sample S / V-BWO.

[0053] The catalytic performance of the prepared vanadium-sulfur co-doped titanium dioxide photocatalyst was evaluated under the aforementioned experimental conditions, and the degradation rate of active blue was determined to be 87.8%.

Claims

1. A method for preparing a bismuth tungstate visible light photocatalyst co-doped with vanadium sulfide, characterized in that... Using sodium tungstate, bismuth nitrate, thiourea, citric acid, ammonium metavanadate, and urea as raw materials, the process includes the following steps: (1) Dissolve 0.05 g of urea in deionized water and stir until dissolved. Add bismuth nitrate and sodium tungstate, wherein the molar ratio of bismuth nitrate to sodium tungstate is 2:

1. Stir until clear to obtain bismuth tungstate BWO solution, which is solution A. (2) Prepare an aqueous solution of thiourea and citric acid in deionized water as a sulfur source, wherein the molar ratio of citric acid to thiourea is 1.2:1; prepare an aqueous solution of ammonium metavanadate and oxalic acid in deionized water as a vanadium source, wherein the molar ratio of oxalic acid to ammonium metavanadate is 2:

1. (3) After mixing the sulfur source and vanadium source, add them dropwise to solution A. The molar ratio of thiourea and bismuth tungstate (BWO) is 1:100 to 1:5, and the molar ratio of ammonium metavanadate and BWO is 1:100 to 1:

20. Stir until the solution becomes a sol. (4) The sol was transferred to the reaction vessel, and after being hydrothermally treated at 180°C for 20 hours and cooled, the product was separated by centrifugation and washed three times with deionized water and anhydrous ethanol, and dried at 80°C to obtain the bismuth tungstate visible light catalyst sample S / V-BWO co-doped with vanadium sulfide.

2. The method for preparing the bismuth tungstate visible light photocatalyst co-doped with vanadium sulfide according to claim 1, characterized in that, Prepare according to the following steps: (1) In a 100 mL transparent beaker, add 80 mL of deionized water and 0.05 g of urea and stir to dissolve; add bismuth nitrate pentahydrate and stir until clear, then add sodium tungstate dihydrate, wherein the molar ratio of bismuth nitrate to sodium tungstate is 2:1, stir for 20 minutes to obtain solution A; (2) Citric acid and thiourea are added sequentially to deionized water and stirred for 2 hours as a sulfur source. The molar ratio of citric acid to thiourea is 1.2:

1. Ammonium metavanadate and oxalic acid aqueous solution are prepared in deionized water as a vanadium source. The molar ratio of oxalic acid to ammonium metavanadate is 2:

1. (3) After mixing the sulfur source aqueous solution and the vanadium source aqueous solution, add them dropwise to solution A. The molar ratio of thiourea to BWO is 1:100, and the molar ratio of ammonium metavanadate to BWO is 1:

20. Stir vigorously for 4 hours during this process until the solution becomes a sol. (4) The obtained sol was transferred to a reaction vessel, hydrothermally treated at 180°C for 20 hours, cooled, centrifuged to separate the product, and washed three times with deionized water and anhydrous ethanol alternately. The product was then dried at 80°C to obtain the sulfur-vanadium co-doped bismuth tungstate visible light catalyst sample S / V-BWO.

3. The method for preparing the bismuth tungstate visible light photocatalyst co-doped with vanadium sulfide according to claim 1, characterized in that, Prepare according to the following steps: (1) In a 100 mL transparent beaker, add 80 mL of deionized water and 0.05 g of urea and stir to dissolve; then add bismuth nitrate pentahydrate and stir until clear, then add sodium tungstate dihydrate. The molar ratio of bismuth nitrate to sodium tungstate is 2:

1. Stir for 20 minutes to obtain solution A. (2) Citric acid and thiourea were added to deionized water in sequence and stirred for 2 hours as a sulfur source. The molar ratio of citric acid to thiourea was 1.2:

1. Oxalic acid and ammonium metavanadate were added to deionized water and stirred for 2 hours as a vanadium source. The molar ratio of oxalic acid to ammonium metavanadate was 2:

1. (3) The above-mentioned sulfur source and vanadium source aqueous solutions are mixed and added dropwise to solution A. The molar ratio of thiourea to BWO is 1:20, and the molar ratio of ammonium metavanadate to BWO is 1:

50. During this process, the mixture is stirred vigorously for 4 hours to obtain a sol. (4) The obtained sol was transferred to the reaction vessel, and the reaction vessel was placed in a 180°C forced-air oven for hydrothermal treatment for 20 hours. After cooling, the product was separated by centrifugation and washed three times with deionized water and anhydrous ethanol alternately. The product was then dried at 80°C to obtain sample S / V-BWO.

4. The method for preparing the bismuth tungstate visible light photocatalyst co-doped with vanadium sulfide according to claim 1, characterized in that, Prepare according to the following steps: (1) In a 100 mL transparent beaker, add 80 mL of deionized water and 0.05 g of urea, stir to dissolve, then add bismuth nitrate pentahydrate, stir until clear, then add sodium tungstate dihydrate, the molar ratio of bismuth nitrate to sodium tungstate is 2:1, stir for 20 minutes, and this is solution A; (2) Citric acid and thiourea were added to deionized water in sequence and stirred for 2 hours as a sulfur source. The molar ratio of citric acid to thiourea was 1.2:

1. Oxalic acid and ammonium metavanadate were added to deionized water and stirred for 2 hours as a vanadium source. The molar ratio of oxalic acid to ammonium metavanadate was 2:

1. (3) After the above sulfur source and vanadium source aqueous solution are mixed evenly, they are added dropwise to solution A. The molar ratio of thiourea to BWO is 1:10, and the molar ratio of ammonium metavanadate to BWO is 1:

50. During this process, the mixture is stirred vigorously for 4 hours to obtain a sol. (4) The obtained sol was transferred to the reaction vessel, and the reaction vessel was placed in a 180°C forced-air oven for hydrothermal treatment for 20 hours. After cooling, the product was separated by centrifugation and washed three times with deionized water and anhydrous ethanol alternately. The product was then dried at 80°C to obtain sample S / V-BWO.

5. The method for preparing the bismuth tungstate visible light photocatalyst co-doped with vanadium sulfide according to claim 1, characterized in that, Prepare according to the following steps: (1) In a 100 mL transparent beaker, add 80 mL of deionized water and 0.05 g of urea and stir to dissolve; then add bismuth nitrate pentahydrate and stir until clear, then add sodium tungstate dihydrate. The molar ratio of bismuth nitrate to sodium tungstate is 2:

1. Stir for 20 minutes to obtain solution A. (2) Citric acid and thiourea were added to deionized water in sequence and stirred for 2 hours as a sulfur source. The molar ratio of citric acid to thiourea was 1.2:

1. Oxalic acid and ammonium metavanadate were added to deionized water and stirred for 2 hours as a vanadium source. The molar ratio of oxalic acid to ammonium metavanadate was 2:

1. (3) After the above sulfur source and vanadium source aqueous solution are mixed evenly, they are added dropwise to solution A. The molar ratio of thiourea to BWO is 1:5, and the molar ratio of ammonium metavanadate to BWO is 1:

100. During this process, the mixture is stirred vigorously for 4 hours to obtain a sol. (4) The obtained sol was transferred to the reaction vessel, and the reaction vessel was placed in a 180°C forced-air oven for hydrothermal treatment for 20 hours. After cooling, the product was separated by centrifugation and washed three times with deionized water and anhydrous ethanol alternately. The product was then dried at 80°C to obtain sample S / V-BWO.

6. The method for preparing the bismuth tungstate visible light photocatalyst co-doped with vanadium sulfide according to claim 1, characterized in that, Prepare according to the following steps: (1) In a 100 mL transparent beaker, add 80 mL of deionized water and 0.05 g of urea, stir to dissolve, then add bismuth nitrate pentahydrate, stir until clear, then add sodium tungstate dihydrate, the molar ratio of bismuth nitrate to sodium tungstate is 2:1, stir for 20 minutes, and this is solution A; (2) Citric acid and thiourea were added to deionized water in sequence and stirred for 2 hours as a sulfur source. The molar ratio of citric acid to thiourea was 1.2:

1. Oxalic acid and ammonium metavanadate were added to deionized water and stirred for 2 hours as a vanadium source. The molar ratio of oxalic acid to ammonium metavanadate was 2:

1. (3) After the above sulfur source and vanadium source aqueous solution are mixed evenly, they are added dropwise to solution A. The molar ratio of thiourea to BWO is 1:5, and the molar ratio of ammonium metavanadate to BWO is 1:

20. During this process, the mixture is stirred vigorously for 4 hours to obtain a sol. (4) The obtained sol was transferred to the reaction vessel, and the reaction vessel was placed in a 180°C forced-air oven for hydrothermal treatment for 20 hours. After cooling, the product was separated by centrifugation and washed three times with deionized water and anhydrous ethanol alternately. The product was then dried at 80°C to obtain sample S / V-BWO.

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